These discussions of the concepts of truth and value lead us to the final issue that I take to characterize cultural studies of science. Sociological constructivists frequently insist that they merely describe the ways in which scientific knowledge is socially produced, while bracketing any questions about its epistemic or political worth. In this respect, their work belongs to the tradition that posits value-freedom as a scientific ideal. By contrast, cultural studies of scientific knowledge have a stronger reflexive sense of their own cultural and political engagement, and typically do not eschew epistemic or political criticism. They find normative issues inevitably at stake in both science and cultural studies of science, but see them as arising both locally and reflexively. One cannot not be politically and epistemically engaged.